Right-angle crash occurrence at signalized intersections

Right-angle crashes are prone to be severe at signalized intersections. To understand right-angle crash occurrence better and eventually to develop efficient countermeasures, this study investigated the effect of intersection traffic volume, geometric design features, and traffic control and operational features on right-angle crash occurrence at four-leg signalized intersections. Data from a total of 197 such intersections were collected from the Central Florida area. Right-angle crashes were modeled at the intersection, roadway, and approach levels. For the models at roadway and approach levels, crashes were assigned to a certain level, and then the disaggregated crashes were related to the specific roadway or approach features. The generalized estimating equations, which can account for site correlation among repeated observations from the same intersections, were used for the disaggregated models. The cumulative residuals method was used to evaluate the functional forms of the traffic volume and the models' overall performance. For the significant factors identified, the logarithm of the product of the conflicting through volumes, the number of through lanes, and the late-night and early-morning flashing operations is found to affect right-angle crash occurrence consistently. Left-turn offset, angle of the intersection, speed limit on the intersecting roadways, and yellow and all-red intervals also are significant in some models. The variables' relative significance was identified.